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University of California Publications in Zoology [Vol. 23 



Remarks. — From the great development of the supraorbital spines it would 

 appear that this species is referable to the genus Alope White, from which it 

 differs, however, in having a mandibular palp of only two segments instead of 

 three as is characteristic of that genus. 



IV. Group with no supraorbital spines. 



Section a. Rostrum as long as or longer than remainder of carapace. (In this 

 subgroup, with the exception of S. paludicola, the third maxillipeds do not exceed 

 the antennal scale. In 8. gracilis, flexa, carinata, and franciscana the third max- 

 illipeds reach about to the middle of the antennal scale or only slightly beyond 

 the middle. In S. decora they extend well beyond the middle and in S. Jcincaidi 

 nearly to the end of the scale, but in neither do they quite attain its end or at all 

 exceed it. In 8. paludicola, mentioned above, the third maxillipeds slightly exceed 

 the tip of the antennal scale. The length of the third maxillipeds of 8. layi is 

 not known.) ' (For section b, see p. 65.) 



Spirontocaris flexa Eathbun 



Spirontocaris camtschatiea Eathbun, The Fur Seals and Fur-Seal Islands 

 of the North Pacific Ocean, pt. Ill, p. 557, 1899, not S. camtschatiea 

 ( Stimpson ) . 



Spirontocaris flexa Eathbun, Proc. U. S. Nat. Mus., 24, 986, 1902 ; H. A. E., 

 10, 78, fig. 32, 1904. 



Fig. 36. Spirontocaris flexa, 5; a, lateral view of carapace and abdomen, 

 X 2%; b, dorsal view of anterior portion, X 3% (from Eathbun, U. S. N. M.). 



Characters. — Eostrum slender, armed with four or five teeth above, including 

 one or two on the carapace, anterior tooth near middle of rostrum; anterior half 

 of rostrum not limbed above; lower limb narrow and armed with from five to eight 

 spines. Basal spine of the antennules extends beyond the first segment of the 

 peduncle. The abdomen is strongly geniculated at the third segment, which is 

 posteriorly produced and compressed, forming a smooth, rounded carina; sixth 

 segment more than twice but not three times as long as wide, and shorter than 

 the telson. 



